Blocking shortcuts

Hi,

I had a problem where some users could receive shortcuts and others were receiving the mails with the shortcuts stripped out. The users were all on the same 2003 server and running the 2003 client with the same SP. I found that those that could receive them had cached exchange mode switched on. I have looked on the web for an explanation of why cached exchange mode affects the files you can receive but can't find anything. Can anyone explain it please.